interrupting process idea

gistfile1.hs

import Control.Concurrent.STM
import Control.Concurrent.STM.TVar
import Control.Concurrent.STM.TChan
import Data.Map (Map)
import qualified Data.Map as Map

reglock  = newTMVar
registry = newTVar empty

addProcess :: (a -> IO ()) -> TVar c -> b -> IO ()
addProcess f b = do
   v <- atomically $ do
          takeTMVar 
          r <- readTVar registry
          return (Map.lookup b)
   fmap . (maybe (return ()) (killThread v))
   tId <- forkIO $ f
   atomically $ do
          r <-readTVar registry
          writeTVar (insert b Id r)
          putTVar reglock ()